I'm not going to pretend I'm an expert on narwhals. To be completely honest, in my head I just think of them as a seal with a unicorn horn. Or some kind of grey sausage-shaped blob with a pointy bit.
However, it turns out that these 'sea unicorns' have been pissing off scientists for a long time. Why? Because boffins had no idea why they have the long tusk on their heads. Surely it'd be like rhinos and be used as a weapon? Or maybe whoever has the biggest one gets their pick of the ladies?
The truth is a little less interesting.
This video, captured by Adam Ravetch for WWF in Canada, shows something that we've never seen before...
Credit: Storyful/Adam Ravetch
The video shows narwhals using their tusks to stun Arctic cod by hitting them. This immobilises the fish, which makes it easier for the narwhals to eat them.
Senior specialist of Arctic species and ecosystems with WWF-Canada, Brandon Laforest, told National Geographic: "They don't jump like other whales. They are also notoriously skittish.
"This is an entirely new observation of how the tusk is used."
Laforest reckons that they may be used as sensory organs, as he said: "Their tusks are covered in thousands of nerve endings and pores that help narwhals sense the environment around them."
He added: "They can feel their surroundings similar to how a human's broken tooth would have feeling."
Marianne Marcoux, a research scientist for Fisheries and Oceans Canada, added that drones have revolutionised the way in which we can study animals. As narwhals are naturally nervous, any kind of filming involving planes (as most attempts to obtain footage have been in the past) just frightens them off and disrupts any natural behaviours. She said: "Drones are very exciting - we can see things we couldn't see before." So that's pretty cool.
Obviously, the narwhals might still be using their tusks for other stuff, such as ice picking, weapons and maybe even showing off the size to their mates - we don't know. But this is conclusive proof that they're not just decorative. Which is nice.
Featured Image Credit: Storyful/Adam Ravetch